Thoraya A. Farghaly

New pyrazoles incorporating pyrazolylpyrazole moiety: Synthesis, anti-HCV and antitumor activity

Three series of novel pyrazole derivatives 2b-d, 4a-d and 6a-d were synthesized via two step procedure that utilizes hydrazonoyl chlorides 1a-d and enaminones 3a-d and 5a-d, respectively as starting materials. The structures of all the newly synthesized products have been established on the basis of analytical and spectral data. Moreover, some of the products 2-6 were tested against HCV and Subacute Sclerosing Panencephalitis (SSPE). In addition, compounds 2-6 were also tested for the inhibition of peroxynitrite-induced tyrosine nitration and antioxidant activity. The tested compounds are highly effective at very low concentration as anti-HCV, SSPE antioxidant and anticancer in the following ascending order 2d, 4c, 6b, 3b, 6c, 4d, 2b, 2c, 2a, 6a, 5b, 5a, 3a, 4b and 5c. It is worth to mention that all tested compounds are more potent than the reference standards used for comparing activity. All the measurements revealed that the mechanism of action of the anti cancer activities of all the tested compounds is topoisomerase I inhibitor.

Synthesis, anti-HCV, antioxidant, and peroxynitrite inhibitory activity of fused benzosuberone derivatives

Reaction of benzosuberone 1 with dimethylformamide-dimethylacetal (DMF-DMA) gives 2-dimethylamino-methylenebenozosuberone 2 which in turn reacts with heterocyclic amines to furnish new heterocyclic ring systems 6-9. Moreover, enaminone 2 reacts with hydrazine hydrate and hydroxylamine hydrochloride to afford the corresponding benzo[6,7]cyclohepta[1,2-c]pyrazole (10) and benzo[6,7]cyclohepta[2,1-d]isoxazole (12), respectively. In addition, the reactions of enaminone 2 with active methylene compounds afforded benzo[6,7]cyclohepta[1,2-b]pyridines (13-18). The X-ray crystallographic analysis of compounds 6 and 16, were recorded. We demonstrated the ability of nine new synthesized compounds to inhibit Hepatitis C Virus (HCV) and Subacute Sclerosing Panencephalitis (SSPE) due to structural similarity between ribavirin and some of the newly synthesized compounds were they contain triazoles and its bioisosters. In addition, the ability of ten synthesized compounds to react with the biologically relevant reactive nitrogen species, peroxynitrite was investigated indirectly by measurement of their ability to inhibit ONOO(-)-induced tyrosine nitration. The antioxidant activity of these ten compounds was also studied using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay.

Hydrazonoyl Halides as Precursors for New Fused Heterocycles of 5α-Reductase Inhibitors

A new series of benzo[6,7]cyclohepta[1,2‐d]triazolo[4,3‐a]pyrimidines 8a–l was synthesized via reaction of heterocyclic thione 4 or its methyl derivatives 10 with hydrazonoyl halides 5a–l. Also, reaction of compound 4 with a mixture of chloroacetic acid and aromatic aldehyde derivatives gave benzo[6,7]cyclohepta[1,2‐d]thiazolo[3,2‐a]pyrimidin‐3‐ones 12–14. The microanalyses and spectral data of the synthesized compounds are in full agreement with their molecular structure. All the newly synthesized products were screened against 5α‐reductase and showed activities with good ED50 for all compounds.

Synthesis, tautomerism, and antimicrobial, anti-HCV, anti-SSPE, antioxidant, and antitumor activities of arylazobenzosuberones.

2-Dimethylaminomethylene-1-benzosuberone 1 was coupled with diazotized aniline derivatives to afford a series of the hitherto unreported 2-arylazo-1-benzosuberones 3a-i. The tautomeric structure and the effect of substituents on the tautomeric form (s) of the products 3a-i were discussed. Similar coupling of the enaminone 1 with diazonium salts of heterocyclic amines gave the respective fused azolotriazino-benzosuberones. Some of the newly synthesized compounds showed potent antimicrobial, anti-HCV, antioxidant, antitumor (as topoisomerase I inhibitors), and antimicrobial activities.

Synthesis and Antimicrobial Activity of Some New 1,3,4-Thiadiazole Derivatives

New series of 1,3,4-thiadiazoles have been prepared via reaction of 1,3,4-thiadiazolenaminones 1 with N-phenyl 2-oxopropanehydrazonoyl chloride (2) in dioxane in the presence of triethylamine. Also, some new heterocycles incorporating 1,3,4-thiadiazole ring were obtained by reaction of 1,3,4-thiadiazolenaminones 1 with nitrogen-nucleophiles like hydrazine hydrate, 3-amino-1,2,4-triazole and 2-aminobenzimidazole. The structure of the new products was established based on elemental and spectral analysis. The relation between the structure of the products and their activity towards some microorganisms was studied and promising results were obtained.

Synthesis of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones as potential antimicrobial agents

Synthesis of new derivatives of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-one via reaction of 7-(4-bromophenyl)-1,2-dihydro-5-(4-fluorophenyl)-2-thioxopyrido[2,3-d] pyrimidin-4(3H)-one with hydrazonoyl chlorides or reaction of 2-hydrazino-pyrido[2,3-d]pyrimidin-4(3H)-one with different aldehydes followed by cyclization of the products. All the newly synthesized compounds were evaluated for their antimicrobial activities and also their minimum inhibitory concentration against most of test organisms was performed. Amongst the tested compounds displayed excellent activity against all the tested microorganisms except SR and PA.

New and efficient approach for synthesis of novel bioactive [1,3,4]thiadiazoles incorporated with 1,3-thiazole moiety

A series of novel 1,3,4-thiadiazoles incorporated with thiazole moiety was synthesized by reaction of 5-acetyl-2-benzoylimino-3-phenyl-1,3,4-thiadiazole thiosemicarbazone 2 with each of N-phenyl 2-oxo-propanehydrazonoyl chloride 3 and ethyl (N-aryl-hydrazono) chloroacetate 5 in dioxane in basic medium. Also, another series of 1,3,4-thiadiazole incorporated with thiazole moiety was prepared by reaction of 5-acetyl-2-benzoylimino-3-phenyl-1,3,4-thiadiazole thiocarbohydrazone with each of hydrazonoyl chlorides 3, 5 and 18 under the same reaction conditions. The mechanisms of the studied reactions were discussed and the assigned structure for each of the new products was identified via elemental and spectral data and by alternative method whenever possible. Moreover, the antimicrobial activity for some selected products was screened, and the results obtained exploring the high potency of some of the tested compounds compared with the employed standard bactericides and fungicide.

Synthesis, tautomeric structures, and antitumor activity of new perimidines.

New series of perimidine derivatives and fused perimidines were derived from the reaction of ketene aminals 1 and 2 with diazotized anilines or hydrazonoyl chlorides. In addition, 8,10‐disubstituted‐[1,2,4]triazolo[4,3‐a]perimidines (20a–m) were prepared through the reaction of perimidine‐2‐thione (15) with hydrazonoyl chlorides. The structures of the newly synthesized compounds were established on the basis of spectral data and elemental analyses. Some products were investigated for their antitumor activities against the human breast cancer cell line MCF‐7 and the liver carcinoma cell line HEPG‐2, and the results of some derivatives showed promising activity.

Antimicrobial, antitumor and 5α-reductase inhibitor activities of some hydrazonoyl substituted pyrimidinones.

A series of 2-[N-aryl-2-oxo-2-(4-chlorophenyl)ethanehydrazonoyl]-6-methyl-4(3H)-pyrimidinones 5 were prepared by coupling the diazonium salt of aniline derivatives with 2-(4-chlorobenzoylmethylene)-6-methyl-4(3H)-pyrimidinone 4 in sodium hydroxide solution. The structures of these newly synthesized compounds were confirmed by IR, NMR, mass spectrometry and elemental analyses and the tautomeric structure of these compounds was discussed. All the newly synthesized compounds were screened for their antibacterial and antifungal activities, some of which exhibited moderate activity. Also, the above compounds were evaluated for their antitumor activity against a panel of 60 human tumor cell lines by the National Cancer Institute (NCI), USA. Compounds 5b, 5d and 5i showed good cytotoxic activities against the tested cell lines. In addition, the newly synthesized compounds were screened for their 5α-reductase inhibitor activity and all the tested compounds showed activities in descending order as follows 5b, 5c, 5g, 5j, 5d, 5h, 5f, 5e and 5i.

New Coumarin Derivatives as Potent Selective COX-2 Inhibitors: Synthesis, Anti-Inflammatory, QSAR, and Molecular Modeling Studies.

Two new series of coumarin derivatives incorporating thiazoline and thiazolidinone moieties were designed, synthesized, and investigated in vivo for their anti‐inflammatory activities using the carrageenan‐induced rat paw edema model and in vitro for their inhibitory activities against the human cyclooxygenase (COX)‐1 and COX‐2 isoforms. Most of the synthesized compounds demonstrated exceptionally high in vivo anti‐inflammatory activity and displayed superior GI safety profiles (0–7% ulceration) as compared to indomethacin. All the bioactive compounds showed in vitro high affinity and selectivity toward the COX‐2 isoenzyme, compared to the reference celecoxib with IC50 values ranging from 0.31 to 0.78 μM. The ethyl thiosemicarbazone 2b, thiazoline derivatives 3a, 3b, 5b, 6a, and 7f, and the thiazolidinone compounds 8b and 9a showed the highest in vivo and in vitro anti‐inflammatory activities with remarkable COX‐2 selectivity. Quantitative structure–activity relationship study (QSAR) was done and resulted in a highly predictive power R2 (0.908). A molecular docking study revealed a relationship between the docking affinity and the biological results.